(1) Field of the Invention
This invention relates to planar surface antennas having two segments, each comprising two conducting etched patterns on respective insulating substrates. A single antenna is used to form an omni-directional antenna and two interconnected antenna elements are used to form a directional antenna.
(2) Description of the Related Art
U.S. Pat. No. 5,714,961 to Kot et al. describes a directional planar antenna having a number of coaxial ring-slot radiating elements.
U.S. Pat. No. 4,559,539 to Markowitz et al. describes a spiral antenna deformed to receive another antenna.
U.S. Pat. No. 5,363,114 to Shoemaker describes planar serpentine antennas.
U.S. Pat. No. 4,509,209 to Itoh et al. describes an integrated planar antenna-mixer device for microwave reception. A diode quad is connected to the antenna.
U.S. Pat. No. 5,124,714 to Harada describes a planar antenna for automobiles.
U.S. Pat. No. 4,410,891 to Schaubert et al. describes a polarized micro-strip antenna. The polarization can be changed from vertical linear to horizontal linear, left circular, right circular or and desired elliptical sense.
U.S. Pat. No. 5,371,507 to Kuroda et al. describes a planar antenna comprising a ground conductor, a dielectric layer laminated on the ground conductor, and a radiation element laminated on the dielectric layer.
U.S. Pat. No. 4,987,421 to Sunahara et al. describes a micro-strip antenna having an annular radiation conductor with a central opening.
U.S. Pat. No. 4,038,662 to Turner describes a broadband antenna in the form of a multiple element interlaced dipole array mounted on a thin elongated strip of dielectric material.
U.S. Pat. No. 5,649,350 to Lampe et al. describes a method of mass producing printed circuit antennas.
U.S. Pat. No. 4,987,424 to Tamura et al. describes an antenna apparatus having flexible antennas made of conductive material on a flexible insulating sheet.
Antennas, including directional and omni-directional planar antennas, are useful in any number of applications including communications and navigation. This invention describes planar, broadband antennas which are relatively easy and inexpensive to fabricate and which can be either directional or non directional.
It is a principle objective of this invention to provide a planar, inexpensive radiating antenna wherein the radiation from the antenna produces an omni-directional radiation pattern.
It is another principle objective of this invention to provide a planar, inexpensive radiating antenna wherein the radiation from the antenna is dependent on the direction from the antenna.
These objectives are achieved by forming two conducting etched patterns on planar substrates of dielectric material. The two conducting patterns are etched in a layer of conducting material formed on the substrates. The first conductor has a planar serpentine shape defining a plurality of parallel, spaced apart radiator elements. The second conductor has comb-like portions interleaved within the radiator elements of the first conductor.
In one embodiment the antenna is formed by using a pair of substrates with etched patterns as described above. The pair of substrates is disposed in the same plane with the second conductor of each half connected to the two electrical terminals of a coaxial cable. The first conductor of each antenna in the pair remains electrically floating and not connected to any conductor. The first conductor is used to provide fine tuning capability to the antenna. The spacing between the two conductors may be adjusted to change both the capacitive and inductive relationship of the two. Additionally, the antenna may be tuned by placing a shunt element between the first and second conductors. This shunt may be moved in order to fine tune the antenna.
In a second embodiment, there will be several pairs of the above described antenna, each placed in another plane, providing an antenna having directional radiation patterns.